The polarization of light can be detected by most humans. There are at least three potential parts of the eye which may act as an analyzer in the detection. It is proposed to evaluate the role of cornea, vitreous and macular lutea in the detection to determine the physical and physiological limits of detection. This will be accomplished by testing normal individuals to a variety of differnt polarized light stimuli. The frequency of monochromatic light, the angle of polarization, the intensity of polarized light will be varied. Subjects will be exposed to direct lights that will travel through different topographical areas of the parts of the eye. The range of variation of individual subjects will be established. Patients with diagnosed early lens cataracts will be tested regarding their ability to detect the direction of polarized light. A statistical evaluation of the data regarding differences between normal individuals and patients with cataracts is planned. It is expected that such evaluation will establish the potential of clinical use of the techniques developed and thereby an early diagnosis of cataracts will be feasible.